The invention relates to a vacuum valve, comprising a valve body with a valve opening which has an axis and is surrounded by a valve seat, a closure member which is adjustable parallel to a longitudinal adjustment direction between an open position, in which said closure member opens up the valve opening, and an intermediate position, in which said closure member covers the valve opening but is raised from the valve seat, and which is adjustable parallel to a transverse adjustment direction between the intermediate position and a closed position, in which said closure member lies against the valve seat, a valve rod which supports the closure member, a longitudinal stroke linear guide which has a longitudinal stroke slide, which is connected to the valve rod, and a longitudinal stroke guide part, by which the longitudinal stroke slide is guided in a linearly displaceable manner in the longitudinal adjustment direction, a longitudinal stroke drive, by which the longitudinal stroke slide is displaceable in relation to the longitudinal stroke guide part in order to adjust the closure member between the open position and the intermediate position, and a transverse stroke drive for adjusting the closure member between the intermediate position and the closed position.
Vacuum valves, in which, in order to close the vacuum valve, the closure member is first of all displaced in a longitudinal adjustment direction, which lies parallel to the valve rod, from an open position into an intermediate position, in which the closure member covers the valve opening, but is still raised from the valve seat, and, as a result, is placed against the valve seat in a transverse adjustment direction lying at an angle to the longitudinal adjustment direction, are also referred to as L valves.
In the case of a non-generic design of L valves, the valve rod is mounted pivotably about an axis, which is at right angles to the longitudinal adjustment direction, in order to permit the adjustment of the valve plate from its intermediate position into its closed position and back. In order to pivot the valve rod about the axis, use can be made here of slotted guides, as is known, for example, from U.S. Pat. No. 6,237,892 B1, U.S. Pat. No. 7,066,443 B2 or US 2012/0258242 A1.
In the case of L valves, in which, in order to adjust the closure member between the intermediate position and the closed position, a parallel displacement of the closure member takes place in a transverse adjustment direction at an angle, in particular at right angles, to the longitudinal adjustment direction, according to a conventional embodiment drive elements for adjusting the closure member between the intermediate position and the closed position are arranged on a supporting unit supporting the closure member, wherein the supporting unit is located within the valve housing of the vacuum valve and is attached to a valve rod which is led out of the vacuum region of the vacuum valve. Such embodiments of L valves are disclosed, for example, in U.S. Pat. Nos. 6,056,266 A, 6,899,316 B2 and 7,611,122 B2. In this connection, U.S. Pat. Nos. 6,056,266 A and 7,611,122 B2 also disclose sequence controls in order to ensure the correct sequence of actuation of the piston-cylinder units. A further such sequence control for an L valve is revealed in U.S. Pat. No. 8,177,190 B2.
An L valve, in which a linear displacement of the closure member between the intermediate position and the closed position takes place, wherein both the drive for the adjustment of the closure member between the open position and the intermediate position and the drive for the adjustment of the closure member between the intermediate position and the closed position are arranged outside the vacuum is revealed in WO 2010/034046 A1. A block which displaceably supports the valve rod in the longitudinal adjustment direction and to which the drive for the adjustment of the valve rod in the longitudinal adjustment direction is also attached is displaceable here linearly in a transverse adjustment direction lying at right angles to the longitudinal adjustment direction, wherein this linear displacement takes place by piston-cylinder units acting in this direction.
U.S. Pat. No. 7,762,527 B2 also presents an embodiment of an L valve, in which the drives for the linear adjustment of the closure member in the longitudinal adjustment direction and in the transverse adjustment direction are arranged outside the vacuum. One possible embodiment makes provision here for the piston-cylinder unit for adjustment of the closure member in the longitudinal adjustment direction to be mounted displaceably in relation to a valve housing in the transverse adjustment direction, which lies at right angles to the longitudinal adjustment direction, by a linear guide.
A vacuum valve of the type mentioned at the beginning is disclosed in WO 2014/075757 A1. A longitudinal stroke linear guide, by which the valve rod is guided displaceably in the longitudinal adjustment direction, is formed here by a transmission piece, which is connected to the valve rod, in a manner corresponding to a longitudinal stroke slide which is guided displaceably along rod-shaped guide parts. The rod-shaped guide parts are displaceable in a transverse adjustment direction lying at right angles to the longitudinal adjustment direction and can be displaced in the transverse adjustment direction by a transverse stroke drive formed by pneumatic piston-cylinder units. For the displacement of the valve rod in the longitudinal adjustment direction, use is also made of pneumatic piston-cylinder units, the valve rods of which are connected to the transmission piece, wherein this connection permits movability of the transmission piece in relation to the valve rods in the transverse adjustment direction. A disadvantage of the device disclosed in this document is the relatively complicated design of the unit having the drive elements and guide elements, which leads to the vacuum valve being more expensive. It would also be difficult in the case of this vacuum valve to use different types of drives according to choice.